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authorStanislav Kinsbursky <skinsbursky@parallels.com>2013-01-04 15:35:03 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2013-01-04 16:11:46 -0800
commit3fcfe78658695b424314ddb76abc8d58b4fc98e6 (patch)
tree755f48f8377acf7e226f0168bfacb870aba7781e /ipc
parent51eeacaa07d1372a7bc9612548ffe6cd846f4f2f (diff)
downloadlinux-3fcfe78658695b424314ddb76abc8d58b4fc98e6.tar.gz
ipc: add more comments to message copying related code
Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: James Morris <jmorris@namei.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'ipc')
-rw-r--r--ipc/msg.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/ipc/msg.c b/ipc/msg.c
index 8493e1d7e35..950572f9d79 100644
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -770,6 +770,10 @@ static long do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz)
}
#ifdef CONFIG_CHECKPOINT_RESTORE
+/*
+ * This function creates new kernel message structure, large enough to store
+ * bufsz message bytes.
+ */
static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz,
int msgflg, long *msgtyp,
unsigned long *copy_number)
@@ -881,6 +885,10 @@ long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp,
msg = ERR_PTR(-E2BIG);
goto out_unlock;
}
+ /*
+ * If we are copying, then do not unlink message and do
+ * not update queue parameters.
+ */
if (msgflg & MSG_COPY)
goto out_unlock;
list_del(&msg->m_list);